Question 1

How does retop reduce STL triangle count?

Accepted Answer

retop uses iterative edge collapse driven by quadric error metrics. For each pair of connected vertices, it computes a cost of merging based on surface deviation, then collapses the cheapest pair until the target triangle count is reached.

Question 2

Does retop upload my STL file to a server?

Accepted Answer

No. The web UI simplifies files locally in your browser — the STL never leaves your machine. The REST API processes uploads server-side but stores nothing after returning the simplified file.

Question 3

What target ratio should I pick for 3D printing?

Accepted Answer

For FDM printing of parts up to 200 mm, 25-50 percent of the original triangles is almost always enough. Resin printing can go to 15 percent on smooth parts. Sharp mechanical features need 60-80 percent.

Question 4

Can I use retop from the command line?

Accepted Answer

Yes. The REST API accepts STL uploads via curl: curl -X POST 'https://retop.app/api/v1/simplify?ratio=0.5' -F 'file=@model.stl' -o reduced.stl

Drop your STL file